class D<T>  {
    void foo(D<?> x){
        bar<error descr="'bar(D<?>, D<? super java.lang.Object>)' in 'D' cannot be applied to '(D<capture<?>>, D<capture<?>>)'">(x,x)</error>;
    }
    <T> void bar(D<? extends T> x, D<? super T> y){}
}